There are great online resources explaining torches and what they are primarily used for, so I won't repeat that info. Go to the metalworkers' resource called Ganoksin for this succinct torch round-up for jewellers.
The wonderful Kate Richbourg has a great video on Craftsy explaining torches and their differences. The video series is free and reviews how to use the micro torch to make basic soldered rings. She uses a Blazer in this video.
Rio Grande has a great series of videos on their site to help you with all kinds of techniques and tools. This useful video by Mark Nelson explains a variety of torches.
So here's my take on things. I've tried most of these torches. I own a big propane torch, which I get out and use on the back deck when I'm doing a lot of torch enamelling. I have a MAPP gas torch (this one and the propane torch can be purchase for around $60 at the hardware store) that I use for forging and twisting heavy gauge wire and metal as well as brazing. I have a Blazer torch (OK, maybe I have four of them) that I use for small soldering projects.
My favourite torch, the one I turn to most often for enamelling, flame colouring metal, fold forming and soldering, is the wide mouthed butane torch. It's the most versatile torch if you only want to invest in one torch for now, in my humble opinion. Its flame is adjustable for finer work, but can also, at its fullest, heat up heavy gauge metal for foldforming quite quickly. It's easy to hold onto and manoeuvre and doesn't overheat with constant use. Its barrel is larger and holds enough butane so that I'm not constantly refilling it.
Here's a picture of my torch working hard for me! It's over four years old, and did stop working for a few months after the mouth of it ended up dunked in a quenching bowl (it dried out and came back to life.) I use it all the time, take it to classes and put it through a lot of use and abuse. Maybe it's time to retire it and buy a new one.
I'm interested in your opinion on torches. Which one is your favourite? Any stories to share?